Data/hora: 06/06/2024 01:25:37

Provedor de dados: | 56
País: | Brazil
Título: | L- and DL-carnitine induce tetanic fade in rat neuromuscular preparation
Autores: | Lopes,G.; Bazotte,R.B.; Curi,R.; Alves-Do-Prado,W.
Data: | 2003-09-01
Ano: | 2003
Palavras-chave: | Carnitine; Skeletal muscle; Tetanic fade; Atropine.
Resumo: | Carnitine, a structurally choline-like metabolite, has been used to increase athletic performance, although its effects on neuromuscular transmission have not been investigated. It is present in skeletal muscle and its plasma levels are about 30 to 90 µM. Using rat phrenic nerve diaphragm preparations indirectly and directly stimulated with high rate pulses, D-carnitine (30 and 60 µM), L-carnitine (60 µM) and DL-carnitine (60 µM) were shown to induce tetanic fade (D-carnitine = 19.7 ± 3.1%, N = 6; L-carnitine = 16.6 ± 2.4%, N = 6; DL-carnitine = 14.9 ± 2.1%, N = 6) without any reduction of maximal tetanic tension. D-carnitine induced tetanic fade in neuromuscular preparations previously paralyzed with d-tubocurarine and directly stimulated. The effect was greater than that obtained by indirect muscle stimulation. Furthermore, previous addition of atropine (20 to 80 µM) to the bath did not reduce carnitine isomer-induced tetanic fade. In contrast to D-carnitine, the tetanic fade induced by L- and DL-carnitine was antagonized by choline (60 µM). The combined effect of carnitine isomers and hemicholinium-3 (0.01 nM) was similar to the effect of hemicholinium-3 alone. The data suggest that L- and DL-carnitine-induced tetanic fade seems to depend on their transport into the motor nerve terminal.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000900017
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2003000900017
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.36 n.9 2003
Fonte: | info:eu-repo/semantics/openAccess